Old hard drives can be found for free.....they really DO have some of the most powerful permanent magnets available.

The magnets in some of the throw-a-way IDE drives of the last seven years contain magnets that easily sell for very large sums. Those are really high-end magnets. Magnetrons (in microwave ovens) have nice toroid shapes but are not quite the same level of quality.

You can get most of what you want for free if you use your imagination. Keep you money in your pocket and always use Ebay last.